Dynamo-electric machinery



vl. H. ST.KH. MAWDSLEY AND F. .lOl-IL, Sn.

DYNAMO ELECTRIC MACHINERY.' APPLICATION man MAR.12.19H.

J. H. ST. H. MAWDSLEY AND H. F.10EL,SR.

DYNAMO ELEcTmc' MACHINERY.

. APPLlCATlON FILED MAR.12,1917. 1,347,647.

Patented J uly, 27, 1920,

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ToaZZ whom it may concern;- j y Be it known vthat-we, JOHN (HERBERT S'r. HiLL MAwDsLEY, a subject ofthe King of Great Britain and Ireland, anda residentin Dursley, Gloucester, England, and HENRY FRANCIS JOEL, the senior, a subject oftheV King of GreatBritain and Ireland',-and a resident in Forest Gate, Essex, England, have invented new and useful improvements in Dynamo-Electric Machinery, of which the following isagspecificationf This invention relates to dynamo electric machines of the type describedin the specification of Letters Patent No. 15487, dated 21st July, 1908, granted lto J ohnk Wesley Burleigh, in which only one interpoleA is provided with Veach pair of main poles and in whichthe main magnetic flux almost en-V tirely passes throughthe portion ofthe yoke between two adjacent mainpoles. `In machines of this type, the pairs of main poles are of U-formation, the limbs forming the two poles being parallel one to the other.

In dynamo electric machines. in accordance with this invention, the poles of each` pair of main poles are arranged, as usual, symmetrically about the center line between them, but, instead of the poles being parallel one to the other as above described, they are inclined one to the other in ysuchwise that the faces of the magnetizing `or field coils,

which extendin a direction atfright angles to the .axes of the poles, shall be at right angles, or approximately so, to a line vdrawn through the center ofthe armature and approximately midway between the center line above referred to and the adjacent edge of the pole. Y'

`Referring to the accompanying drawings, which are more or less diagrammatic in nature; 1

Figure 1 showsa dynamo electric machine in accordance with this invention;

Figs. 2 to4 Yshow sectional side views of modified forms of interpoles shown lin Fig. 1.

1 is the main frame or yoke of the ma-l chine and 2a, 2b the main poles. v 3 is an interpole and 4 is the armature. The cross sectional area of the yoke between the members of each pair of main poles 2a, 2l isapproximately the same as the cross sectional area of the poles, and the frame of the machine, to which the interpoles are fixed,

whilebeing of sufficient strength, is made of "Q LYNAMmELEcTnIc MACHINERY.

specimen# Leiters rfnt. f Patented 'July 27,1920. c Applicatifm' med Marci; "121917f'seria1 iva-154,345. `1

tively considerably greater than the magnetic reluctance of the yoke between the vmembers of each pairof main poles. The main poles 2, 2b, instead of being parallel oneto the other as heretofore proposed, arev equallyinclined to the center-line A-B' between them;`l` 5, 6 are the magnetizing, or field coils of the main poles; the end faces of these coils are in planes at right angles to the axes of the main poles. The magnetizing o r-field coils 5, 6 are preferably wound, as shown, in two (or more) sections, a space beings-left between'the sections andalso beftween the coils of adjacent pairs of poles at 9, owing to the divergence of the poles from the center, and the special arrangement of Vthe main poles and the smaller section of the frame 1 provide a considerable space at 10 between the main poles and the interpole 3. These spaces9, 10 allow the air to circulate all round and between the coils. The inclination of the main poles is such that the end face of each magnetizing or field coil 5 is at right angles, or approximately so, to a line drawn through the center of the armature 4 and approximately midway between the center line A-B and the adjacent edge 7 of the body of the main pole upon which the coil is carried. The dimensions and arrangement of the magnetizingor field coils iing or field coil 5 between the members of a pair of main poles is extended together so as in combination to lie in or near the neutral zonev over the armature coils undergoing commutation in known manner.

In machines having divided coils as 5, 6, one section only may be, as shown, extended to the center between the pairs ofpoles and over or near the neutral zone and this Section may, with advantage, be the series winding of a compound wound machine or part ofthe field coil of a balancer, the other section being closely wound around the pole.

8 are Ventilating ducts formed in the frame to which the interpoles are fixed.

The interpole 3 illustrated in Fig. 2, which is a sectional side view of the interpole shown in Fig. l, is attached tothe yokenear ,p one edge and is inclined inward of the yoke shown inA Figs. l and' 2. In the interpoles' shown in Figs. 3 and 4 no separate pole shoe is employed. These interpoles provide for better ventilation, which is a characteristic of= this invention.

Aninterpole 3 is placed between each pairl of mainfpoles so that there is only one inten pole for each pair of main poles. From the foregoing description it will be apparent that the angle between an interpole and a neighboring main poleis less thana right angle. Y

he improvements, as described, effect an economy in the manufacture of this type of dynamo electric machinery, provide a more efficientventilation, a reduction of the leakagebetween the poles and a decrease in the sparking under varying loads.

1;.Af dynamo electric machine having non-radiali pole cores in pairs and interpoles between said pairs of pole cores, said pole cores having a substantially constant diameter the length of said pole cores, in combination with a plurality of field coils upon a pole of said polecoresfone ofsaid coils being a series coil of larger diameter than the pole core and spaced to provide a Ventilating duct from a peripheral pole end along the surface of the said pole to the outside surfacev of the remaining field ycore winding.l l u 2. A dynamo electric machine according to claim l in whichpole cores are` provided with series field coils near the periphery of said pole cores, saidlatter field coils shifted peripherally `so as to provide internal ventilating ducts between the coils and the said pole cores.

3. In a dynamo electric machine a field excitation system comprising a field pole devoid `of a Apole shoe` horn at one end, a fieldcoil having externaland internal diameters sufficientlylarge so that when shifted peripherally with respect to said field pole the coil whenmounted shall reach into the commutating zone and also provide an internal Ventilating duct for the centrifugal air from an armature.

Dated this 23rd day of February, 1917.

JOHN HERBERT S'l. HILL MAWDSLEY. HENRY FRANCIS JOEL, SEMO?. 

